Regional colorectal cancer screening program using colonoscopy on an island: a prospective Nii-jima study

Objective: Colorectal cancer screening program using fecal immunochemical test had been conducted on an isolated island named Nii-jima. However, the participation rate of the program had been approximately 12%, which was lower than average level of Japan. This study aimed to evaluate the participation rate, safety and efficacy of a colorectal cancer screening program using colonoscopy on the island. Methods: Educational campaigns were actively conducted every month using information bulletins and special propaganda pamphlets. The primary recommended modality was colonoscopy, followed by fecal immunochemical test. The participants of this program were 1671 individuals aged 40-79 years (men, 819; women, 852). Results: A total of 789 (47.2%) individuals provided consent for this screening program, and 89.2% (704/789) of participants chose colonoscopy as the primary screening procedure. The completion rate of total colonoscopy was 99.7%, and there was no complication during this program. Detection rates of invasive cancer, intramucosal cancer, advanced neoplasia and any adenoma were 0.9% (n = 6), 2.4% (n = 17), 11.8% (n = 83) and 50.0% (n = 352), respectively. The adenoma detection rate and incidence of advanced neoplasia were significantly higher in men than in women in all age groups. Conclusions: The colorectal cancer screening program using colonoscopy that was conducted on an island achieved considerably higher participation rate than the conventional screening program using fecal immunochemical test. Completion rate and safety of screening colonoscopy were excellent during this program.